Add a task page for setting up kuberc

[soltysh]

This is an umbrella issue

What would you like to be added
Add a new task page that explains how to write a kuberc file, which allows customizing kubectl behavior.

Why is this needed
With the work around kuberc we need to ensure there's a proper documentation in place, so users can understand how to correctly leverage the file and make kubectl easier to use for them,.

Comments
Partially addressed by #50913 and #50961.

[soltysh]

/sig cli
/language en
/priority important-longterm
/triage accepted